1. Field of the Invention
The present invention is related generally to an improved data processing system, and in particular to a method and apparatus for controlling a microwave cooking unit. Still more particularly, the present invention is directed to a computer implemented method, computer usable program code, and an apparatus for dynamically detecting metal objects placed in a microwave cooking area.
2. Description of the Related Art
A microwave cooking unit, such as a microwave oven, is a device employing microwave radiation to cook, heat, melt, or defrost food items. For example, one of the most popular food items cooked in a microwave oven is microwave popcorn. Microwave ovens generally utilize a magnetron, which is a device for generating microwaves. Microwave ovens are popular because they are capable of cooking food in a short amount of time by utilizing microwaves rather than cooking by heat convection as in standard gas or electric ovens.
Microwaves are radio waves within a frequency range that is absorbed by water, fats, and sugars but not by most plastics, glass, or ceramics. For example, when a ceramic bowl filled with soup is heated in a microwave, the microwaves are absorbed by the water and fat molecules, but not by the ceramic container. The microwaves excite the water and fat molecules to generate heat relatively evenly throughout the soup, although the temperature within the microwave oven itself remains at approximately room temperature. Thus, it is sometimes said that microwave ovens cook food from the inside out.
Unlike most plastics, glass, or ceramics, however, most metals reflect microwaves. When a metal object is left inside a microwave oven cooking chamber during operation of the microwave oven, the metal object can reflect the microwaves back into the magnetron, where arcing can occur. This arcing can damage the magnetron.
In addition, the presence of metal objects inside a microwave oven cooking chamber can result in the production of sparks and/or create a potential for a fire or explosion. For example, metal utensils, a metal staple in a paper or cardboard takeout bag or container, aluminum foil, tin foil, or metal plates can cause the formation of sparks.
In addition, the presence of a metal object can cause a potential for a fire and/or an explosion to occur. For example, paper takeout bags containing food item are sometimes stapled shut and cardboard takeout boxes sometimes include a metal handle. If such a takeout container is placed inside a microwave for heating without removing the staples and/or metal handle, the metal can form sparks that cause the paper or cardboard to catch fire.
Mistakenly placing a metal object inside a microwave oven can cause sparking, fires, explosions, and/or damage to the magnetron. In cases where the magnetron is damaged, the microwave oven heating element will not function. In such a case, the microwave oven is generally rendered useless for the purposes of microwave cooking.